Manufacture of multiconductor cables

ABSTRACT

A multiconductor cable core is provided with a barrier of sealing material by pumping the sealing material from a thermostatically controlled storage vessel to a cable feeding station while at a temperature just above that at which crystallization begins and transferring sealing material from the cable feeding station to the cable core while still at such a temperature. The material is cooled to effect crystallization by abstraction of heat by the insulated conductors constituting the core to cause sufficient sealing material to become solidified to form an effective moisture barrier. The sealing material while at such a temperature is preferably continuously circulated around a ring main in which is located a plurality of cable feeding stations for transferring the material to a core curing a conventional stranding process.

United States Patent [72] Inventor Brian John Wardley Billinge, nearWigan, England [21] Appl. No. 810,092 [22] Filed Mar. 25, 1969 [45]Patented Aug. 31, 1971 [73] Assignee British Insulated Callenders CablesLimited London, England [32] Priority Apr. 5, 1968 [33] Great Britain[31] 16462/68 [54] MANUFACTURE OF MULTICONDUCTOR CABLES 16 Claims, 4Drawing Figs.

[52] 11.8. C1 57/7, 57/162,156/48 [51] Int. Cl B65h 81/08, HOlb13/14,1-l01b 13/24 [50] Field 01 Search 57/3, 7, 35, 59,60, 148,149,162;156/48 [56] Relerences Cited UNITED STATES PATENTS 1,886,447 11/1932Slade 57/7 1,966,575 7/1934 Whiting 57/7 57/7 2,093,206 9/1937 MullerPrimary Examiner.1ohn Petrakes AttarnevWebb, Burden, Robinson & WebbABSTRACT: A multiconductor cable core is provided with a barrier ofsealing material by pumping the sealing material from a thermostaticallycontrolled storage vessel to a cable feeding station while at atemperature just above that at which crystallization begins andtransferring sealing material from the cable feeding station to thecable core while still at such a temperature. The material is cooled toeffect crystallization by abstraction of heat by the insulatedconductors constituting the core to cause sufficient scaling material tobecome solidified to form an effective moisture barrier. The sealingmaterial while at such a temperature is preferably continuouslycirculated around a ring main in which is located a plurality of cablefeeding stations for transferring the material to a core curing aconventional stranding process.

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O g -r\ Inventor BRIAN JOHN WARDLEY B MM BMLMJ [ML llorm'y:

PATENTEUAUGSHQH '3 6 967 sum 2 OF 2 Uoooo'b Invenlor BRIAN JOHN WARDLEYU441, 3mm WA A llorneys MANUFACTURE OF MULTICONDUCTOR CABLES Thisinvention relates to telecommunication cables of the kind comprising amultiplicity of plastics insulated conductors enclosed within awaterproof sheath. If such cables, whether buried in the ground or drawninto ducts, become locally damaged to an extent to allow water to enterthrough the damaged sheath, the water will travel along the cablethrough the interstices between the insulated conductors and between theconductors and the sheath and so will have an adverse effect upon theelectrical characteristics of the whole cable length, for instance byshorting of circuits via pinholes in the wire insulation.

With the object of preventing water that has entered through a defectivesheath or joint casing from travelling even a short distance along thecable from the point of entry it has been proposed to fill theinterstices between the insulated cable conductors and between them andthe cable sheath throughout the entire length of the cable with waterimpermeable filling material.

For forming a continuous barrier throughout the length of a cable it isdesirable to use a waterproof impermeable material which will not drainunder the influence of gravity or such hydrostatic pressure as may arisein the event of damage to the cable sheath or joint casing but whichwill permit relative sliding movement of the plastics insulatedconductors or group of conductors over one another during such bendingof the cable as occurs during manufacture and installation of the cable.Examples of such materials are:

a. Microcrystalline petroleum waxes b. Mixtures of microcrystallinepetroleum waxes and oils, for instance petroleum jelly c. Low molecularweight, high Malt Flow lndex polyethylene or polypropylene of asemisolid or greaselike nature d. Mixtures of petroleum jelly,microcrystalline petroleum waxes, polyethylene, polysioutylene andaluminum stearate.

e. a blend of two or more of filling materials (a.) to (d.).

The choice of filling material is to some extent limited by the methodof introducing the filling material into the cable core and by thenature of the dielectric of the conductors forming the core.

In the manufacture of plastics insulated multiconductor cables that arefilled throughout with water impermeable filling material, it has beenconsidered necessary to transfer such material from a storage vessel tothe cable and to apply it to the cable under superatmospheric pressureby some form of pump. It is difficult however to pump such material inits solid condition because almost inevitable cavitation will occurwithin the storage vessel and cause a break in the feed to the pump. lfpumping in such condition can be achieved, at the required rates offlow, for example 100 ft./min. (30.7 m./min.) at 4 gallons/min. (18.2litres/min.) in a pipe having a crosssectional area of 1 sq. in. (6.5sq. cms. some breakdown of the crystal bonds in the material will resultthus degrading the material by lowering its viscosity, so rendering itless capable of forming a barrier permanently resistant to water underpressure;

Degradation of the material occasioned by pumping is reduced if pumpingtakes place while the material is at a temperature just above thetemperature at which crystallization begins and it has been proposed toprovide a cable core with a barrier of sealing material by pumping thesealing material from a thermostatically controlled storage vessel to acable feeding station while at a temperature just above that at whichcrystallization begins and cooling the material to effectcrystallization while transferring it from said cable feeding station tothe cable core. We have now found that it is not necessary to cool thesealing material while it is transferred from the cable feeding stationto the cable core and that a core can be provided with a satisfactorybarrier of sealing material if the sealing material is transferred tothe cable core while the material is still at a temperature just abovethat at which crystallization begins and is cooled to effectcrystallization by abstraction of heat by the insulated conductorsconstituting the core.

I Accordingly the present invention consists of a method of providing amulticonductor cable core with a barrier of sealing material whichcomprises pumping the sealing material from a thermostaticallycontrolled storage vessel to a cable feeding station while at atemperature just above that at which crystallization begins,transferring the sealing material from the cable feeding station to thecable core while still at such a temperature, and cooling the materialto effect. crystallization by abstraction of heat by the insulatedconductors constituting the core to cause sufficient sealing material tobecome solidified to form an effective barrier to the passage ofmoisture along the core.

The rate of delivery of sealing material to the core may be adjusted inrelation to the linear speed of travel of the core but preferably therate of delivery of sealing material is such that, for any linear speedof travel at which the core is required to travel, sufficient materialwill be applied to the core to form an effective barrier when it becomessolidified.

By a temperature just above that at which crystallization begins ismeant a temperature at which the sealing material is in a sufficientlyliquid state to permit pumping of the material -to be effected withsubstantially no degradation of the material occurring. Where, as ispreferred, the sealing material is a mixture of microcrystallinepetroleum waxes and oils, such as petroleum jelly, the temperature atwhich crystallization begins is approximately 70 C. and the temperaturejust above the crystallization temperature at which the material can bepumped without causing substantial degradation is approximately 76 C.

- The invention also includes apparatus for carrying out the aforesaidmethod comprising a thermostatically controlled storage vessel forstoring the sealing material while at a temperature just above that atwhich crystallization begins, the vessel being connected to one or morethan one cable feeding station having means for applying sealingmaterial to the cable core and, connected between the storage vessel andthe applicator means of the or each cable feeding station, means forwithdrawing sealing material from the storage vessel and for controllingthe rate of delivery of the material to the applicator means.

It is preferred to have a feeding station at each stranding point and totransfer sealing material in a liquid state to the core at, or shortlyin advance of, the closing die of the stranding head, in which case thenumber of feeding stations in operation will be the same as the numberof layers of conductors, pairs or quads laid up around the centerconductor, pair or quad, but where the first layer is laid up around agroup of two or more conductors, pairs or quads it may be advantageousto have a feeding station at the point where these two or moreconductors, pairs or quads are brought together to form a core center. Afurther feeding station may be located at the outlet end of the finalclosing die but we have found that this is not generally necessary.

Preferably the sealing material is applied to the core through anapplicator die constituting or forming a separable part of the closingdie associated with a stranding head and in this case the sealingmaterial is applied! to the surface of the last-formed layer ofconductors, pairs or quads, to the surface of each conductor of thelayer of conductors, pairs or quads being brought down by the closingdie onto said last-formed layer, and to the surface of the layer ofconductors, pairs or quads formed at said closing die, thereby ensuringthat the cable interstices are completed filled with sealing material.Each feeding station may have its own individual source of supply andsurplus material (i.e. material that is not carried forward through thestranding head) in a liquid or semisolid state may either be returned tothe storage vessel to be brought back to the requisite temperature in oron its way to such vessel or it may be collected for reprocessing by thesupplier.

Alternatively there may be a common source of supply for some or all ofthe feeding stations at a machine or for some or all of the feedingstations at a number of machines. In such case sealing material ismaintained in a thermostatically controlled storage vessel at atemperature just above that at which crystallization begins and iscontinuously circulated through a ring main which is thermally insulatedand may be trace heated to maintain the circulating material at theappropriate temperature. From this ring main sealing material whilestill at such a temperature is bled off at intervals and fed to thefeeding stations. Transfer of the sealing material to the cable core ispreferable controlled by a valve at each feeding station but it may becontrolled by a metering pump. Surplus material from the feedingstations cannot in this case be fed back into the ring main unless it isfirst brought back to the temperature of the circulating material. Itwill generally be preferable either to pump it back into the commonstorage vessel or to collect it for reprocessing. Preferably the sealingmaterial is circulated in the ring main at a much higher rate than theaggregate rate at which it is withdrawn for transfer to the cable core,for example at a rate to times as great. Such circulation is preferablyeffected by a pump having an intake in a part of the storage vesselremote from the part to which the circulating material'is returned.

The invention will now be described in more detail, and by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic illustration of apparatus suitable for use inproviding a multiconductor cable core with a barrier of sealing materialwhich extends throughout the length of the cable core, while the cablecore is being manufactured by a conventional stranding machine,

FIG. 2 is an end view of an applicator die of the apparatusdiagrammatically illustrated in FIG. 1,

FIG. 3 is a section on the line llllll in FIG. 2, and

FIG. 4 is a diagrammatic illustration of an alternative form ofapparatus for providing a continuous barrier of sealing material in amulticonductor cable core.

Referring to FIG. 1, the apparatus comprises a storage vessell for thesealing material thermostatically controlled in any convenient mannerand, connected to the lower part of the vessel, aring main 2 comprisingan outward pipe 3, in which is connected a pump 5, and a return pipe 4.At each end of a plurality of locations spaced at intervals along thelength of the return pipe 4, of which three only are shown, is a cablefeeding station 11 at which sealing material at a temperature just abovethat at which crystallization begins and hence in a liquid state "iscontinuously bled off from the ring main 2 and transferred to the cablecore. Each cable feeding station 11 has a' valve 12 for controlling therated of flow of sealing material being bled off from the system 2 and adie 15 for applying the material to the cable core. The die 15 isdetachably secured to the entry end of the closing die of a strandinghead.

The storage vessel 1 and all piping of the ring main 2 are lagged andthe piping is provided with steam trace heating. In the lower part ofthe storage vessel 1 there are provided stainless steel steam heatingcoils 7 for use when the sealing material in the vessel has been allowedto go solid, as for instance when commencing circulation of the sealingmaterial in preparation for applying sealing material to a cable core.During circulation of the sealing material and application of thematerial to a cable core the sealing material in the thermostaticallycontrolled storage vessel 1 is maintained in a liquid state by anysuitable method.

At each feeding station 11 sealing material, which is being pumpedaround the ring main 2 in a liquid state, is continuously bled off andtransferred in a liquid state into the applicator die 15. The rate ofdelivery of the sealing material in a liquid state to the cable core viaeach applicator die 15 is controlled by its associated valve 12. Thesealing material is cooled to effect crystallization by abstraction ofheat by the insulated conductors constituting the core to causesufficient sealing material to become solidified to form an effectivebarrier to the passage of moisture along the core. Circulation of thesealing material through the ring main 2 will generally be maintained ata'rate 5 to 10 times as great as the aggregate rate at which it iswithdrawn from the ring main at the cable feeding stations 1 l. g

Surplus material spewing from each applicator die 15 is returned to acollecting tank 16 where any loss of temperature may be compensated bytrace heating the tank. From the collecting tank 16 the surplus materialis pumped by a scavenge pump 18 back through a filter 17 into the upperpart of the storage tank 1 from where, after it has been brought back tothe temperature of the circulating material, it can be recirculatedthrough the ring main 2. At each feeding station 11, a pipe 19 isprovided for feeding sealing material directly from the ring main 2 intothe collecting tank 16 when required, as for instance preparatory tostarting up the sealing operation.

As will be seen on referring to FIGS. 2 and 3, each of the dies 15 bywhich the sealing material in a liquid state is applied to the cablecore during its manufacture comprises a body 21 having a smoothlytapering bore 22 which is bellmouthed at its entry end and which, at itsexit end, corresponds to or is somewhat greater than the circumscribingcircle of the cable core passing through the die. The outer surface ofthe wall of the body 21 is stepped at three locations along its lengthto form three cylindrical portions, 23, 24 and 25. Portion 23 at theexit end of the die is externally screw threaded. In the portion 24 ofthe die wall are three ports 26 for entry of'sealing material which aredistributed uniformly around the axis of the die and are inclined to itso as to impart to the liquefied material a component of movement in thesame axial direction as the direction of travel of the cable corepassing through the die. A sleeve 27, which has an internal diametercorresponding to the external diameter of the cylindrical portion 25 andwhich has at one end an inwardly directed internally screwthreadedflange 28, is screwed on to the end portion 23 of the body 21 until thesleeve fits tightly over the cylindrical portion 25 and abuts the stepthereof. A hole 29 in the wall of the sleeve 27 is bounded by anupstanding continuous wall 31 and provides access for flow of sealingmaterial in a liquid state to an annular chamber 30 lying between theinternal surface of the sleeve 27 and the cylindrical portion 24. Thewall 31 bounding the hole 29 is internally screw threaded for connectionto a pipe carrying sealing material from the feeding station 11. Sealingmaterial in a liquid state is fed from the annular chamber 30 to thecable core passing through the die via the ports 26. As previouslystated the die 15 is detachably secured to the entry end of the closingdie of a stranding head.

The rate of flow of sealing material into each die 15 is at leastsufficient to maintain a pool of material in aliquid state in theannular chamber 30 and in the bell-mouth of the die. Surplus materialfrom each die 15, if any, is allowed to fall into its associated Vcollecting tank 16 to be reheated and pumped back into the storage tankas previously described.

By way of example it is mentioned that in providing a multiconductorcable core comprising pairs laid in six stranded layers with acontinuous barrier of petroleum jelly having a drop melting point withinthe approximate range 73 to 78 C. using 'the method and apparatusdescribed with reference to FIGS. 1 to 3; the petroleum jelly in aliquid state and at a temperature of approximately 76 C. is delivered tothe core at each of six applicator dies at a rate of approximately 2gaL/min. (9.1 litres/min), the linear speed of travel of the core beingapproximately 225 ft./min. (69 m./min.).

Although in the foregoing description reference is made to thecontinuous filling of a single 'multiconductor cable core during itsmanufacture, it will be appreciated that the ring main may serve two ormore adjacently sited cable-making machines.

In the alternative form of apparatus shown in FIG. 4, each strandinghead of a conventional stranding machine has at its inlet end anapplicator die 45 which is of a form similar to that shown in FIGS. 2and 3 and at which sealing material in a liquid state is fed to a cablecore from an individual thermostatically controlled tank 41 in which thesealing material is maintained in a liquid state in any suitable manner,for instance by heating coils 47. The sealing material in a liquid stateis fed to the applicator die 45 through a pipe 42 constituting the cablefeeding station, and filter 43 by a metering pump 44. Surplus materialspewing from the applicator die 45 falls back into the tank 41 where itis reheated and pumped back to the applicator die. In advance of theapplicator die 45 a pipe 46 is provided for feeding sealing materialbeing pumped through the pipe 42 directly back into the tank 41 whenrequired, as for instance preparatory to starting up the sealingoperation.

As in the method using the first form of apparatus sufficient sealingmaterial is caused to become solidified by abstraction of heat by theinsulated conductors constituting the core to form in effective barrierto the passage of moisture along the core.

The process of fully filling a multiconductor cable in accordance withthe present invention has the advantage that it eliminates substantiallyall mechanical working of the sealing medium--generally petroleumjelly-and so eliminates the separating out of oil from the wax whichoccurs under the action of shear brought about by pumping such materialwhen in its solid state.

What I claim as my invention is:

l. A method providing a cable core comprising a multiplicity ofinsulated conductors with a barrier of sealing material which will notdrain under the influence of gravity or such hydrostatic pressure as mayarise in the event of damage to the sheath of the cable but which willpermit relative sliding movement of the insulated conductors over oneanother during such bending of the cable as occurs during manufactureand installation of the cable, which method comprises the steps of:

a. pumping the sealing material from a thermostatically controlledstorage vessel to a cable feeding station while at a temperature justabove that at which crystallization begins,

b. transferring the sealing material from the cable feeding station tothe cable core while still at such temperature, and

c. cooling the material to effect crystallization by abstraction of heatby the insulated conductors constituting the core to cause sufficientsealing material to become solidified to form an effective barrier tothe passage of moisture along the core.

2. A method as claimed in claim 1, wherein the sealing material in thestorage vessel is maintained at a temperature just above that at whichcrystallization begins and is continuously pumped from the storagevessel and circulated around a ring main to one or more cable feedingstations located in the ring main:

3. A method as claimed in claim 2, in which the cable core is beingmanufactured by the conventional stranding process employing a strandingmachine having at least one stranding head and associated closing die,wherein the sealing material is applied to the core at the closing dieof each stranding head of the stranding machine.

4. A method as claimed in claim 3, in which the first layer ofconductors of the cable core is laid up around a group of at least twoconductors forming a core center, wherein sealing material at atemperature just above that at which crystallization begins is deliveredthrough an applicator die at the point where the two conductors arebrought together to form the core center.

5. A method as claimed in claim 2, wherein surplus material spewing in aliquid or semisolid state from an applicator die at each cable feedingstation is returned to the storage vessel and is brought back to therequisite temperature.

6. A method as claimed in claim 2, wherein the sealing material ispumped around the ring main at a rate substantially exceeding theaggregate rate of flow of material from the cable feeding stations tothe cable core.

7. A method as claimed in claim 1, wherein each of a plurality of cablefeeding stations is fed with sealing material from a separate source ofsupply.

8. A method as claimed in claim 7, wherein surplus sealing materialspewing in a liquid or semisolid state from an applicator die at eachcable feeding station is returned to the storage vessel associated withthe die and is brought back to the requisite temperature.

9. Apparatus for use in providing a cable core comprising a multiplicityof insulated conductors witha barrier of sealing material which will notdrain under the influence of gravity or such hydrostatic pressure as mayarise in the event of damage to the sheath of the cable but which willpermit relative sliding movement of the insulated conductors over oneanother during such bending of the cable as occurs during manufactureand installation of the cable, which apparatus comprises:

a. a thermostatically controlled storage vessel for storing the sealingmaterial,

b. means for maintaining the sealing material at a temperature justabove that at which crystallization begins,

c. at least one cable feeding station connected to the storage vessel,

d. means at the feeding station for applying sealing material to thecable core, and

e. connected between the storage vessel and the applicator means of thecable feeding station, means for withdrawing sealing material from thestorage vessel and for controlling the rate of delivery of the materialto the applicator means.

10. Apparatus as claimed in claim 9, wherein the thermostaticallycontrolled storage vessel is connected to a ring main for the sealingmaterial in which is connected means for continuously withdrawingsealing material from the storage vessel, driving it around the ringmain and back into the vessel, and a cable feeding station is providedat at least one location in the ring main.

11. Apparatus as claimed in claim 10, wherein the means for controllingthe rate of delivery of the material to the applicator means is a valve.

12. Apparatus as claimed in claim 10, wherein each of a plurality ofapplicator means has associated with it a heated tank for collectingsurplus material spewing from the applicator means, a pipe extends fromthe collecting tank to the storage vessel, and a scavenge pump isprovided for pumping the surplus material from the collecting tank backinto the storage vessel.

13. Apparatus as claimed in claim 9, wherein each of a plurality ofthermostatically controlled storage vessels is connected to a separatecable feeding station.

14. Apparatus as claimed in claim 13, wherein each means for withdrawingsealing material from the storage vessel and controlling its rate ofdelivery to the applicator means is a metering pump.

15. Apparatus as claimed in claim 13, wherein each storage vessel is solocated with respect to the applicator means of its associated cablefeeding station as to collect surplus material spewing from theapplicator means.

16. Apparatus as claimed in claim 9, wherein the applicator meanscomprises a die which forms at least a part of the closing die of astranding head of a stranding machine and which has a number of portsfor entry of sealing material, which ports are distributed uniformlyaround the axis of the die and are inclined to it so as to impart tosealing material entering the die a component of movement in the sameaxial direction as the direction of travel of the cable core.

1. A method providing a cable core comprising a multiplicity ofinsulated conductors with a barrier of sealing material which will notdrain under the influence of gravity or such hydrostatic pressure as mayarise in the event of damage to the sheath of the cable but which willpermit relative sliding movement of the insulated conductors over oneanother during such bending of the cable as occurs during manufactureand installation of the cable, which method comprises the steps of: a.pumping the sealing material from a thermostatically controlled storagevessel to a cable feeding station while at a temperature just above thatat which crystallization begins, b. transferring the sealing materialfrom the cable feeding station to the cable core while still at suchtemperature, and c. cooling the material to effect crystallization byabstraction of heat by the insulated conductors constituting the core tocause sufficient sealing material to become solidified to form aneffective barrier to the passage of moisture along the core.
 2. A methodas claimed in claim 1, wherein the sealing material in the storagevessel is maintained at a temperature just above that at whichcrystallization begins and is continuously pumped from the storagevessel and circulated around a ring main to one or more cable feedingstations located in the ring main:
 3. A method as claimed in claim 2, inwhich the cable core is being manufactured by the conventional strandingprocess employing a stranding machine having at least one stranding headand associated closing die, wherein the sealing material is applied tothe core at the closing die of each stranding head of the strandingmachine.
 4. A method as claimed in claim 3, in which the first layer ofconductors of the cable core is laid up around a group of at least twoconductors forming a core center, wherein sealing material at atemperature just above that at which crystallization begins is deliveredthrough an applicator die at the point where the two conductors arebrought together to form the core center.
 5. A method as claimed inclaim 2, wherein surplus material spewing in a liquid or semisolid statefrom an applicator die at each cable feeding station is returned to thestorage vessel and is brought back to the requisite temperature.
 6. Amethod as claimed in claim 2, wherein the sealing material is pumpedaround the ring main at a rate substantially exceeding the aggregaterate of flow of material from the cable feeding stations to the cablecore.
 7. A method as claimed in claim 1, wherein each of a plurality ofcable feeding stations is fed with sealing material from a separatesource of supply.
 8. A method as claimed in claim 7, wherein surplussealing material spewing in a liquid or semisolid state from anapplicator die at each cable feeding station is returned to the storagevessel associated with the die and is brought back to the requisitetemperature.
 9. Apparatus for use in providing a cable core comprising amultiplicity of insulated conductors with a barrier of sealing materialwhich will not drain under the influence of gravity or such hydrostaticpressure as may arise in the event of damage to the sheath of the cablebut which will permit relative sliding movement of the insulatedconductors over one another during such bending of the cable as occursduring manufacture and installation of the cable, which apparatuscomprises: a. a thermostatically controlled storage vessel for storingthe sealing material, b. means for maintaining the sealing material at atemperature just above that at which crystallization begins, c. at leastone cable feeding station connected to the storage vessel, d. means atthe feeding station for applying sealing material to the cable core, ande. connected between the storage vessel and the appliCator means of thecable feeding station, means for withdrawing sealing material from thestorage vessel and for controlling the rate of delivery of the materialto the applicator means.
 10. Apparatus as claimed in claim 9, whereinthe thermostatically controlled storage vessel is connected to a ringmain for the sealing material in which is connected means forcontinuously withdrawing sealing material from the storage vessel,driving it around the ring main and back into the vessel, and a cablefeeding station is provided at at least one location in the ring main.11. Apparatus as claimed in claim 10, wherein the means for controllingthe rate of delivery of the material to the applicator means is a valve.12. Apparatus as claimed in claim 10, wherein each of a plurality ofapplicator means has associated with it a heated tank for collectingsurplus material spewing from the applicator means, a pipe extends fromthe collecting tank to the storage vessel, and a scavenge pump isprovided for pumping the surplus material from the collecting tank backinto the storage vessel.
 13. Apparatus as claimed in claim 9, whereineach of a plurality of thermostatically controlled storage vessels isconnected to a separate cable feeding station.
 14. Apparatus as claimedin claim 13, wherein each means for withdrawing sealing material fromthe storage vessel and controlling its rate of delivery to theapplicator means is a metering pump.
 15. Apparatus as claimed in claim13, wherein each storage vessel is so located with respect to theapplicator means of its associated cable feeding station as to collectsurplus material spewing from the applicator means.
 16. Apparatus asclaimed in claim 9, wherein the applicator means comprises a die whichforms at least a part of the closing die of a stranding head of astranding machine and which has a number of ports for entry of sealingmaterial, which ports are distributed uniformly around the axis of thedie and are inclined to it so as to impart to sealing material enteringthe die a component of movement in the same axial direction as thedirection of travel of the cable core.